The present invention relates to optical systems for endoscopes, for macroscopic overall view observation, and for microscopic partial view observation after contact of the objective viewing aperture with the object.
According to French Patent Specification No. 2,437,194 it is known that an optical system of an endoscope utilised for examinations may also be utilised for detailed observation of an object, e.g. such as the surfaces of organs or the like, the object placed in direct contact with the objective forming an image behind the ocular, and is examined by means of an attached eyepiece. The manual placing of an eyepiece on the ocular is inappropriate for practical application however, since a previously scrutinised detail cannot be found again or found only with great difficulty, in view of the risk of an accidental change in position of the optical system with respect to this detail said risk being connected with the handling operation.
According to German Offenlegungschrift No. 29 48 394, the endoscope optical system utilised therein is provided with a first ocular section of particular magnification, the beam path of which may optionally be directed at a second ocular of different magnification by means of a deflection device displaceable transversely to the longitudinal axis. A setting wheel is also provided for the focussing operation. The manual switching action and the required transfer of the eye from one ocular to the other lead to accidental positional changes of the endoscope optical system and are already very difficult to operate in practice for this reason. An endoscope optical system is also known from the German Gebrauschsmuster specification No. 74 40 701, which comprises a displaceable lens, by means of which it is possible to examine an object at varying magnification. Because of a minimum distance which has to be maintained, a direct contact of the objective viewing aperture with the object for microscopic viewing is impossible and this optical system is consequently not suitable for microscopic detail observation. A second disadvantage is that the two ranges of different magnification lack any substantial micro and macro ranges.
It is an object of the invention to provide an optical system, which substantially avoids the aforesaid disadvantages, which apart from overall view observation at a distance from the object also allows of a microscopic detail enlargement under direct contact of the optical system with the object, and wherein the two ranges of considerably different magnification have a pronounced micro range and macro range in each case.